H Biology Chapter 2 2/2

Atoms are composed of protons with a positive charge, neutrons with no charge, and electrons with a negative charge. All three subatomic particles together make up the structure of an atom.

An element is a substance that is composed of only one type of atom. Nucleus refers to the central part of an atom containing protons and neutrons. Cell is a basic structural and functional unit of living organisms. Carbon is a chemical element.

Atoms are the basic building blocks of matter, not cells, molecules, or carbon. While molecules and cells are made up of atoms, atoms themselves are the fundamental units of matter.

Electrons of an atom are located outside the nucleus and orbit it in specific energy levels.

When atoms gain energy, the electrons move to higher energy levels. This results in increased potential energy within the atom.

Carbon can form covalent bonds with a variety of other atoms, not just carbon atoms. Having four electrons in its outer energy level allows carbon to form stable bonds with up to four other atoms, leading to the vast diversity of organic compounds.

A covalent bond is formed when atoms share electrons to achieve stability, unlike ionic bonds where electrons are transferred completely.

When an atom gains or loses electrons, it becomes charged and is called an ion. A molecule consists of bonded atoms, a nucleon is a particle found in an atomic nucleus, and an element is a substance made up of only one type of atom.

In an ionic bond, electrons are transferred from one atom to another, leading to the formation of ions with opposite charges that are attracted to each other. In a covalent bond, electrons are shared between atoms, leading to the formation of a stable molecule.

Reaction three most likely occurred in the presence of a catalyst, which can lower the activation energy required for the reaction to proceed. This allows the reaction to occur faster or at lower temperatures compared to its uncatalyzed form. Therefore, options B, C, and D are incorrect as they do not accurately describe the characteristics of reaction three.

The correct answer is B because the difference in the graphs of reaction 2 and reaction 3 represents the different activation energies needed for those reactions. Option A is incorrect because the speed of a reaction is not solely determined by the energy requirement. Option C is incorrect because the energy levels of reactants and products are different concepts. Option D is incorrect because not all statements presented are true.

Catalysts function by providing an alternative pathway for the reaction to occur, lowering the activation energy required. This does not violate the laws of nature but rather facilitates the reaction. Additionally, the use of catalysts does not necessarily require higher temperatures nor reactants to be quickly added. This allows for more efficient chemical processes.

Enzymes are known for their ability to increase the rate of chemical reactions in living organisms by acting as biological catalysts. They do not heat up molecules, provide CO2, or absorb excess heat for reactions to occur.

Enzymes are biological molecules that catalyze (speed up) chemical reactions in living organisms. Each enzyme is highly specific to a particular chemical reaction, and there can be thousands of different enzymes present in a single organism, each specialized for a different reaction. This high level of specificity allows cells to carry out a wide variety of metabolic processes efficiently.

When a molecule gains an electron, it is undergoing reduction, not oxidation. The confusion often arises because the terms oxidation and reduction are often discussed in tandem as redox reactions.

Oxidation-reduction reactions play a crucial role in transferring energy within living organisms, enabling the movement of energy from molecule to molecule.

The concentration of a solution refers to the amount of solute that is dissolved in a fixed amount of the solution. This measurement is crucial in various fields such as chemistry, biology, and medicine to determine the strength or potency of a solution.

In a neutral solution, the concentration of hydronium ions (H3O+) equals the concentration of hydroxide ions (OH-), resulting in a balanced pH level. The presence of equal numbers of hydronium and hydroxide ions denotes neutrality.

A solution with a pH of 11 is considered alkaline as pH levels above 7 are alkaline or basic in nature.

An acidic solution has a pH value that is less than 7 on the pH scale, indicating a higher concentration of H+ ions.

Buffers play a crucial role in regulating pH levels in living organisms by resisting drastic changes in acidity or basicity. The incorrect answers are not accurate representations of the function and importance of buffers.

The chemical formula for a water molecule is H2O, which indicates that each molecule of water contains two hydrogen atoms and one oxygen atom.